The present invention relates to a sealing film for toner cartridge ensuring the formation of an opening with a substantially constant width after tearing a central longitudinal portion of said sealing film.
Up to now many researches have been made in order to find a sealing film for sealing a toner cartridge, which is flexible and which after longitudinal tearing, is suitable for defining an opening with a substantially constant width.
Prestel et al (U.S. Pat. No. 5,110,646) discloses a sealing member not having a preferred tearing direction, which is provided with a series of adjacent perforations. Such perforations cause leakage of toner particles, whereby the use of such sealing member has not be considered as useful by the man skilled in the art.
Films having a preferred tearing linear direction are nowadays used extensively for sealing toner container. However, even with means for lowering the initial tearing force, the opening formed after tearing a central strip is reduced most of the time, some times increased, from the initial tearing end up to the terminal tearing end.
For ensuring a substantially constant width of the opening formed after tearing a central strip from the sealing film, EP-0 788 033 (Canon) has proposed to use a sealing film comprising a base layer having a tearing directionality, a guide layer having a tearing guide portion formed by a laser processing, and a laser barrier layer provided between said base layer and said guide layer. Such a film is expensive and the risk to have an undesired tearing is high as the base layer and barrier layer can induce an undesired tearing.
U.S. Pat. No. 5,523,828 (Canon) discloses a sealing film provided with a flexible tape, a first portion of which attached to the film defines the strip to be torn out, while the other portion of which acts as pulling means. The aim of the first portion of the flexible strip which extends on one surface of the sealing film (i.e. from one free end of the film up to the opposite free end of the film) is to ensure a minimum width of the strip to be torn so as to define an opening or passage for the toner with a minimum width.
Tests made by Applicant have shown that when a film with a tearing directionality is provided with two grooves parallel to the preferred tearing direction, a constant width of the opening formed after tearing the central strip could not be ensured.
It has now been observed that when making cuts or grooves perpendicular to the preferred tearing direction of the film and when tearing the strip in a direction perpendicular to the preferred tearing direction, it was possible to obtain an opening with a substantially constant width.
It has also been observed by Applicant that by selecting the correct material for the sealing member, it was possible to avoid the problem of contamination of the toner with fibrous material.
It has further been observed that when using a too thin film for making an one piece material comprising:
the sealing film provided with cuts or grooves perpendicular to the preferred tearing direction, and
the pulling means,
a risk exists that the pulling means is broken, especially at the place where the pulling means is bent over the sealing film. The present invention has thus for aim to further solve this problem.
The invention relates to a sealing member for a toner cartridge, said sealing m having a sealing film with a substantially longitudinal portion to be torn out be first end and a second end, said longitudinal portion extending between a first line a second line and to being adapted to be torn between the first end and the second end, wherein said sealing film comprises a layer with a thickness comprised between 20 xcexcm and 1 mm, whereby said layer is connected to a pulling means, said pulling means comprising at least a layer comprising fibres extending in a direction forming an angle comprised between xe2x88x9260xc2x0 and +60xc2x0 advantageously between xe2x88x9245xc2x0 and +45xc2x0, preferably between xe2x88x9215xc2x0 and +15xc2x0, with respect to the tearing direction of the longitudinal portion to be torn.
The fibres of the layer of the pulling means are advantageously substantially parallel to each other, for example welded together.
Preferably, the layer of the pulling means has a portion extending at least partly on the longitudinal portion to be torn out.
According to an embodiment, the sealing film layer has at least one preferred substantially linear tearing direction, said layer being provided with at least:
a first longitudinal surface element selected from the group consisting of cuts, grooves, recesses and combinations thereof and extending along the first line, and
a second longitudinal surface element selected from the group consisting of cuts, grooves, recesses and combinations thereof and extending along the second line,
whereby said longitudinal surface elements extend in a direction of at least 5xc2x0 with respect to the preferred substantially linear tearing direction.
According to another embodiment,
the substantially longitudinal portion to be torn out is associated to a pulling means having a portion intended to extend at least partly over one face of the film before the tearing of said portion,
whereby at least the portion of the pulling means adjacent to the first end of the portion to be torn out has a sufficient tearing resistance for preventing a separation between the pulling means and the substantially longitudinal portion to be torn out during at least the tearing of the first end of the substantially longitudinal portion of the film to be torn out.
Advantageously, at least the portion of the pulling means intended to extend at least partly over one face of the film before the tearing of the substantially longitudinal portion of the film has a sufficient tearing resistance for preventing a separation between the pulling means and the first end of the substantially longitudinal portion to be torn out during the tearing of the substantially longitudinal portion of the film to be torn out from its first end up to its second end.
According to an embodiment, the substantially longitudinal portion to be torn out is associated to a pulling means having a portion intended to extend at least partly over one face of the film before the tearing of said portion, whereby at least the portion of the pulling means is intended to be bent before the tearing of the substantially longitudinal portion, so that the pulling means extends at least partly over one face of the film before the tearing of the substantially longitudinal portion of the film. The pulling means has a sufficient tearing resistance for preventing a separation between the pulling means and the first end of the substantially longitudinal portion to be torn out during the tearing of the substantially longitudinal portion of the film to be torn out from its first end up to its second end.
According to a preferred embodiment, the pulling means is made in a material having a sufficient tearing resistance for preventing a rupture of the pulling means during the tearing of the substantially longitudinal portion from its first end up to its second end. Such a pulling means is for example a longitudinally oriented film (for example a film having for example a preferred tearing direction perpendicular to the preferred tearing direction of the sealing film), film comprising a mat of fibres, thicker flexible film made of adjacent fibres, for example welded together, films made in a material comprising fibres with a high tearing resistance, film with fibres with a high stretching resistance, fibres laminated with one or more layers, etc.
According to a detail of an embodiment, the sealing film is provided with a means for lowering the initial tearing force. When the sealing film comprises surface elements, the longitudinal surface elements (grooves, recesses, etc.) are preferably associated with a means for lowering the initial tearing force.
Preferably, the surface elements are located on a face of the film intended to be directed towards the toner cartridge. Possibly said elements are located on a face of the film not intended to be directed towards the toner cartridge. According to a possible specific embodiment, the two opposite faces of the film are provided with one or more surface elements.
For example, the longitudinal surface elements form an angle comprised between 5xc2x0 and 175xc2x0 with respect to the preferred substantially linear tearing direction and extend only partially into the thickness of the sealing layer so as not to transverse the sealing layer. Preferably, the longitudinal surface elements form an angle between 45xc2x0 and 135xc2x0 with respect to the preferred substantially linear direction. Most preferably, longitudinal surface elements form an angle of about 90xc2x0 with respect to the preferred substantially linear direction.
The layer of the pulling means has advantageously a portion extending on the longitudinal portion to be torn out from the first end up to about the second end. Preferably, the sealing means has a first face intended to be directed towards the toner cartridge and a second face opposite to said first face, whereby the layer of the pulling means has a portion extending on the second face of the portion of the film to be torn out from its first end up to its second end.
According to an embodiment, at least one connecting means links the substantially longitudinal portion to be torn out with the pulling means, whereby said connecting means has a sufficient tearing resistance for preventing a separation between the pulling means and the substantially longitudinal portion to be torn out during at least the tearing of the first end of the substantially longitudinal portion of the film to be torn out.
Advantageously, at least one connecting means links the substantially longitudinal portion to be torn out with the pulling means, whereby said connecting means has a sufficient tearing resistance for preventing a separation between the pulling means and the substantially longitudinal portion to be torn out during the tearing of the substantially longitudinal portion from its first end up to its second end.
For example, said connecting means is selected from the group consisting of welding means, gluing means, clipping means, and mixtures thereof.
Preferably, said connecting means is selected from the group consisting of welding lines, welding points, welding surfaces, gluing points, gluing lines, gluing surfaces, and mixtures thereof.
According to a detail of an embodiment, the pulling means is made in a material having a sufficient tearing resistance for preventing a rupture of the pulling means during the tearing of the substantially longitudinal portion from its first end up to its second end.
According to an embodiment, the connecting means is a means increasing the tearing resistance of the pulling means at least for a portion of the pulling means adjacent to the first end of the substantially longitudinal portion to be torn out.
For example, the connecting means is a means increasing the tearing resistance of the pulling means at least for a portion of the pulling means adjacent to the first end of the substantially longitudinal portion to be torn out, as well as the first end of the substantially longitudinal portion to be torn out.
For example, the connecting means increasing the tearing resistance is selected from the group consisting of flexible tapes, longitudinal welding lines, flexible layers attached to the layer with preferred substantially linear tearing direction, and mixtures thereof.
According to an embodiment, the film and pulling means are made from a same material consisting of fibres welded together or bound together by means of a resin or glue. In this case, the fibres of the pulling means are directed so as to form an angle with respect to the direction of the fibres of the sealing layer, for example an angle comprised between 60xc2x0 and 120xc2x0.
According to a specific embodiment, the sealing film has a substantially longitudinal portion to be torn out between a first end and a second end with a variable width, said longitudinal portion extending between a first line and a second line and to being adapted to be torn between a first end and a second end, wherein said sealing film comprises a layer with a thickness comprised between 20 xcexcm and 1 mm (preferably with at least one preferred substantially linear tearing direction), said layer being provided with a means reducing the width of the portion adjacent to the second end of the longitudinal portion to be torn out during the tearing of said second end.
Advantageously, the surface elements are located on a face of the film intended to be directed towards the toner cartridge. Possibly said elements are located on a face of the film not intended to be directed towards the toner cartridge. According to a possible specific embodiment, the two opposite faces of the film are provided with one or more surface elements.
For example, the longitudinal surface elements form an angle comprised between 5xc2x0 and 175xc2x0, preferably between 45xc2x0 and 135xc2x0, most preferably about 90xc2x0, with respect to the preferred substantially linear tearing direction and extend only partially into the thickness of the layer so as not to transverse the layer.
According to an embodiment of the sealing member,
the longitudinal portion of the sealing film extends between a first upper line and a second lower line, whereby when the toner cartridge is placed in a copier, laser printer, fax machine or printer, the second lower line is substantially horizontal and extends at a level lower than the level at which the first upper line extends, and
the first upper line is associated to a means intended for reducing the width of the portion adjacent to the second end of the longitudinal portion to be torn out during the tearing of said second end.
The sealing member of the invention can be associated to or can further comprise a slotted support (such as a foam support) and/or gluing means for attaching the sealing film on a face of the toner holder or for attaching the slotted support on a face of the toner holder, and/or a removable support for facilitating the placement of the sealing film on a toner holder, and/or a removable paper (silicon paper for example) for protecting the gluing means or layer for attaching the sealing film or slotted support on the toner holder, and/or a cleaning means so as to remove possible toner particles present on the portion to be torn during the tearing operation, etc.
The invention relates also to a toner holder provided with one sealing member as disclosed here above.
The invention relates thus also to a toner holder selected from the group consisting of toner container and toner cartridge, said holder being provided with a sealing member with a sealing film for closing an opening of the toner holder, said sealing film having a substantially longitudinal portion to be torn out between a first end and a second end, said longitudinal portion extending between a first line and a second line and to being adapted to be torn between the first end and the second end, wherein sail sealing film comprises a sealing layer with a thickness comprised between 20 xcexcm and 1 mm, whereby said sealing layer is connected to a pulling means, said pulling means, said pulling means comprising at least a layer comprising fibres extending in a direction forming an angle comprised between xe2x88x9260xc2x0 and +60xc2x0 with respect to the tearing direction of the longitudinal portion to be torn.
The toner holder of the invention has advantageously one or more characteristics of the sealing film of the invention.
With respect to the sealing film suitable for the invention, reference is made to U.S. Ser. No. 10/071,254, filed on Feb. 8, 2002 in the name of Jan De Kesel.
Suitable sealing film is disclosed hereafter. Such a film is for example a sealing film for toner cartridge, said film having a longitudinal portion to be torn out, said longitudinal portion extending between a first line and a second line and to be torn between a first end and a second end, wherein said sealing film comprises a layer with a thickness comprised between 20 xcexcm and 1 mm and with a preferred substantially linear tearing direction. Said layer is provided at least with a first longitudinal surface recess, such as a groove, preferably a cut, extending along the first line and a second longitudinal surface recess such as a groove, preferably a cut, extending along the second line, whereby said longitudinal surface elements extend in a direction of at least 5xc2x0 with respect to the preferred substantially linear tearing directions.
The total thickness of the sealing film or at least of the portion thereof to be torn out is preferably lower to 400 xcexcm, such as lower than 300 xcexcm, lower than 200 xcexcm. Examples of thickness are 40 xcexcm, 50 xcexcm, 75 xcexcm, 100 xcexcm, 120 xcexcm, 125 xcexcm, 150 xcexcm, 175 xcexcm.
The film can have a laminated structure, but has preferably a structure comprising at most two laminated layer. When the film is a laminated structure of two layers having parallel tearing directions, it is advantageous to provide the film on both faces with surface elements selected from the group consisting of cuts, grooves, recesses and combinations thereof.
A preferred substantially linear tearing direction is the direction along which a linear tear line extends due to a tearing force.
The layer provided with the longitudinal surface elements (cuts, grooves, recesses, combinations thereof) is preferably a layer which requires means for lowering the initial tearing force, such as cuts, perforations, etc.
Advantageously, said longitudinal surface cuts, grooves, recesses or combinations thereof form an angle comprised between 5xc2x0 and 175xc2x0 with respect to the preferred substantially linear tearing direction and extend partially into the thickness of the layer so as not to transverse the layer.
Advantageously, the longitudinal surface cuts, grooves, recesses or combinations thereof form an angle between 45xc2x0 and 135xc2x0 with respect to the preferred substantially linear direction.
Preferably, the longitudinal surface cuts, grooves, recesses or combinations thereof form an angle of about 90xc2x0 with respect to the preferred substantially linear direction.
Advantageously, the longitudinal surface cuts, grooves, recesses or combinations thereof extend at least at a distance of more than 1 cm from the first end of the portion
Preferably, the longitudinal surface cuts, grooves, recesses or combinations thereof are associated with a means for lowering the initial tearing force.
For example, the cuts, grooves, recesses or combinations thereof are located on a face of the film intended to be directed towards the toner cartridge. Possibly said elements are located on a face of the film not intended to be directed towards the toner cartridge. According to a possible specific embodiment, the two opposite faces of the film are provided with one or more surface elements.
According to a specific embodiment, the first and second longitudinal surface cuts, recesses or grooves are substantially perpendicular to the preferred linear tearing direction, while said first and second longitudinal surface cuts, grooves or recesses extend substantially from the first end up to the second end.
According to a possible embodiment, the film comprises a first series of longitudinal surface cuts, grooves or recesses extending along the first line and a second longitudinal surface cuts, grooves or recesses extending along the second line. For example, the cuts, grooves or recesses of a series are spaced from each other with a distance of less than 10 mm, advantageously of less than 2 mm, preferably of less than 1 mm.
According to a detail of a embodiment, the cuts, grooves or recesses have a maximum depth corresponding to 95% of the thickness of the layer. The maximum depth of the cuts, grooves or recesses depends from the material, its thickness, its rigidity, etc. For example for a polypropylene film (with a linear preferred tearing direction) with a thickness of 125 xcexcm, the maximum depth can be 90% of the mean thickness, advantageously lower than 80% of said mean thickness.
According to another detail of an embodiment, at least one portion of cuts, grooves or recesses has a minimal depth corresponding to at least 10% of the thickness of the layer, preferably corresponding to at least 20% of the thickness of the layer, most preferably corresponding to at least 30% of the thickness of the layer. For material such as polypropylene with a thickness of about 125 xcexcm, the mean depth of the grooves, recesses, etc. is comprised between 10% and 90%, advantageously between 50% and 80% of the mean thickness, for example 60%, 70%, 75%. The minimum depth depends also from the material used, its thickness, its rigidity, etc.
The cuts, grooves or recesses may have a constant or variable depth.
The film is preferably a monolayer film provided with adhesive means. The film can be a bidirectional film or even a tri-directional film (stretched in the three orthogonal direction). The adhesive can be a contact glue, a pressure glue, a hot-melt glue, etc. The adhesive, preferably the hot-melt adhesive can be associated to heating means (which can be removed or not from the adhesive after a heating step), such as conductive means, conductive layer, electric conducting wire or layer, etc. Such adhesive (with or without heating means or removable heating means) can also be used in sealing member comprising a multilayered film. The monolayer film has advantageously a thickness of less than 400 xcexcm, preferably of less than 300 xcexcm, such as 400 xcexcm, 500 xcexcm, 700 xcexcm, 900 xcexcm, 110 xcexcm, 125 xcexcm.
The sealing film is advantageously provided with adhesive means and with a removable protecting layer to be removed for attaching the film on the toner cartridge. The sealing film is preferably provided with a pulling means connected to the portion to be torn. The pulling means is for example be a band attached to the strip to be torn or to a portion of the film forming a prolongation of the strip to be torn out.
The layer of the sealing film and of the pulling means is for example a layer selected from the group consisting of uniaxially oriented polyethylene film, uniaxially oriented polypropylene film, bi phase polymer film, films made of incompatible compounds, biaxially oriented polypropylene, biaxially oriented polyethylene, and mixtures thereof. The layer can be reinforced (for example with a mat of fibres, a non woven material or fabric), non reinforced, laminated or not laminated, glued or not glued to a flexible support, etc.
It has also been observed that the tearing is facilitated or more precise, when reinforcing the lateral edges of the pulling means of the sealing strip, when the pulling means is integral with the sealing member. The invention relates thus also to a sealing member provided with an integral pulling means, the lateral edges of which are reinforced.
Advantageously the surface elements are at least partly made by a ultrasonic treatment.
Preferably, the film has a melting temperature, and the ultrasonic treatment is sufficient for ensuring a heating of the material up to a temperature higher than the melting temperature of the film where said surface elements selected among the group consisting of grooves, recesses, series of distant recesses, series of distant grooves, and mixtures thereof have to be made.
The ultrasonic treatment is advantageously combined with one or more other treatments, such as compression, rolling, etc.